Effect of Hydration on Gluten-Free Breads Made with Hydroxypropyl Methylcellulose in Comparison with Psyllium and Xanthan Gum

Producción CientíficaThe use of hydrocolloids in gluten-free breads is a strategy to improve their quality and obtain products with acceptable structural and textural properties. Hydration level (HL) optimization is important to maximize the hydrocolloids effects on dough and bread quality. This study evaluated the optimum hydration level (OHL) for gluten-free breads prepared with different starch sources (rice flour or maize starch) and hydroxypropyl methylcellulose (HPMC) in comparison with psyllium husk fibre and xanthan gum. Breads with the same final volume and the corrected hydration (CH) were evaluated. The hydration is a key factor that influences the final characteristics of gluten-free breads. Breads made with HPMC had greater dependence on the HL, especially for preparations with maize starch. Psyllium had similar behaviour to xanthan with respect to specific volume and weight loss. Breads manufactured with maize starch and HPMC had low hardness due to their great specific volume. However, in breads made with rice flour, the combined decreased hydration and similar specific volume generated a harder bread with HPMC than the use of psyllium or xanthan. Breads made with HPMC presented higher specific volume than the other hydrocolloids, however combinations among these hydrocolloids could be evaluated to improve gluten-free breads quality.European Regional Development Fund (0612_TRANS_CO_LAB_2_P

Rheological and microstructural evolution of the most common gluten-free flours and starches during bread fermentation and baking

Mechanistic relations between the evolution of the starch/flour structure, dough rheology and bread quality were investigated using the most common flours and starches in gluten-free bread-making. Micrographs showed that the small wheat starch granules filled the spaces of the big granules, forming a uniform starch-hydrocolloid matrix. This granular advantage decreased the consistency and increased the uniformity of wheat-starch based doughs throughout fermentation, as shown by micrographs and the higher critical strain. The viscoelastic properties of the different doughs strongly influenced the bread volume and the crumb texture. Thus, starch-based breads showed higher specific volume and lower hardness, especially those made with wheat starch, whose lower pasting temperature also reinforced the continuous phase of the crumb. On the other hand, the large potato starch granules did not form a continuous starch-hydrocolloid matrix, resulting in breads with the lowest specific volume, elasticity, cohesiveness and resilience, and the highest hardness

Influence of protein source on characteristics and quality of gluten-free cookies

Proteins are essential nutrients in the diet, with the recommended amount of daily protein consumption varying for people with different health status and activity level. Cookies could be an adequate carrier of proteins because of their great acceptability. The aim of this study was to analyse the effect of flour substitution with different types of protein (pea, potato, egg white and whey) in gluten-free cookies. Hydration properties, dough rheology, cookie characteristics (protein content, dimensions, texture) and sensory acceptability were studied. The hydration properties of mixtures with protein were lower than the control, with the exception of pea protein. As for results from rheological analysis, G´ and G” values for pea and potato protein were similar to the control, while egg white and whey protein had lower values. Regarding cookie characteristics, the addition of egg white and whey protein produced harder and wider cookies, respectively. The addition of potato protein yielded cookies with darker edges, but the incorporation of pea protein did not lead to any significant change in cookie parameters. Sensory evaluation showed that the addition of pea protein produced cookies with the same scores as the control sample, signifying that cookies with added pea protein had the best acceptability.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2) and the European Regional Development Fund (FEDER

Assessing influence of protein source on characteristics of gluten-free breads optimising their hydration level

Most gluten-free products have lower protein content than their counterparts with wheat flour. The addition of exogenous proteins could not only be a good option to compensate for this reduction but also a tool to create gluten-free products rich in protein. However, the different water binding capacities of proteins modify dough rheology, which also affects bread volume. Therefore, this study aimed to analyse the incorporation of a high percentage (30%) of several proteins (rice, pea, egg white and whey protein) in gluten-free breads whose hydration levels were adjusted for each protein to achieve the maximum volume. In this way, the breads with vegetal proteins required a higher amount of water than the breads with animal proteins. Moreover, all enriched breads exhibited lower maximum volume values than control, and the ones with whey protein presented the lowest volumes overall. From these results, the rheological behaviour and characteristics (colour, texture and weight loss) of optimized doughs and breads were measured. The doughs with whey protein presented the highest G’ and G’’ values due to their low hydration level, and the ones with egg white protein were very watery. Regarding colour, the addition of protein led to darker crusts, with the ones with whey protein being the darkest. With respect to the control, breads with animal proteins exhibited higher hardness, especially with whey protein, while the ones with vegetal proteins did not present significant differences.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2) and the European Regional Development Fund (FEDER

Fruit and vegetable by-products as novel ingredients to improve the nutritional quality of baking foods

The industrial manufacturing of fruits and vegetables generates approximately 50% by-product waste, causing a negative environmental impact and significant expenses. Nevertheless, fruit and vegetable by-products (FVB) are rich nutrients and extranutritional compounds that contribute to bowel health, weight management, lower blood cholesterol levels and improved control of glycemic and insulin responses. Due to the positive influence of FVB fibers and bioactive compounds during the digestion of glycemic carbohydrates, such as starch, baked goods are ideal food systems to accommodate FVB, since most of them have a high glycemic index. Therefore, this is an area of recent interest with critical environmental, economic and health implications worldwide. However, the utilization of FVB in baked goods leads to the loss of acceptability, in many cases caused by a lack of understanding of the physical structure and composition of FVB and their effects on food quality. The objective of this review is to provide a mechanistic understanding of the impact of the physical structure and composition of FVB on common baked goods and their influence on the nutritional and physical quality of the resulting product. This review will support the use of FVB as ideal ingredients while improving the added value of waste streams.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2) and the European Regional Development Fund (FEDER

Can citrus fiber improve the quality of gluten-free breads?

Producción CientíficaCitrus fiber has a high water absorption capacity, and its properties can be modified by shearing. In this study, the influence of the addition of normal or shear-activated citrus fiber was analyzed in two gluten-free bread formulations. Citrus fiber increases bread optimal hydration and breadcrumb alveolus size due to this high water retention capacity. However, results are negative in the formula based on starches and rice flour because specific volume is significantly reduced, while bread quality improves in the formula based on starches (corn and tapioca). In this case, the breads become less hard and more cohesive, elastic, and resilient, reducing staling. Baking yield also increased due to a greater hydration and a reduced weight loss during baking, without losing acceptability. The mechanical pre-activation of the fiber further increases optimal hydration, without major changes in the quality of the final bread. These effects are associated with cell rupture, and thus the formation of a three-dimensional network, including the increase of surface area and its interaction with water. Citrus fiber increases the hydration of the dough, as well as the cohesiveness, resilience, and elasticity of the crumb, reducing the increase in hardness during storage without affecting acceptability or increasing it.Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (project VA177P20

Physicochemical properties of native and extruded maize flours in the presence of animal proteins

Interest for protein-enriched starchy products has increased, as protein intake moderately higher than current recommendations may provide health benefits for ageing populations. Influence of the substitution of native or extruded flours by 25% or 50% of proteins (collagen, milk, whey or egg white proteins) was studied. Collagen was the only protein that increased water binding capacity (p<0.05) up to 233,72% for mixtures with native and up to 40.85% for mixtures with extruded flours. Regarding gelling properties, regardless used flour, mixtures with 50% of collagen increased water absorption index and swelling power (p<0.05) by ⁓100%, while mixtures with 50% of egg white protein decreased water absorption index by ⁓40% (p<0.05). Pasting viscosity decreased in flour-protein mixtures, except the ones with egg white protein, that increased. Endotherm peaks shifted to higher temperatures when proteins were present. Regarding viscoelastic behaviour, when using native flour and higher protein content, gels presented stronger gel behaviour.Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-2-R) and the European Regional Development Fun

Bread enrichment with oilseeds. A review

Producción CientíficaThe use of oilseeds in bakery products has gained popularity in recent years, both for their organoleptic and nutritional characteristics. The aim of this work is to provide an overview of the studies centered on the use of oilseeds (flaxseed, chia, sunflower, pumpkin, sesame and poppyseed) in breads and other bakery products. This review highlights the effect of oilseeds on the mechanical and physical properties of bread according to the enrichment level, origin and way of addition (whole, crushed, oil or mucilage). In general, the incorporation of oilseeds improves the nutritional profile of bakery products with and without gluten, and provides several health benefits. Mucilages of oilseeds can also act as a fat replacer thanks to their properties. The incorporation of oilseeds modifies the rheology of the doughs, the volume of the products and their texture, affecting their organoleptic characteristics and their acceptability. Nevertheless, these changes will depend on the type of seed used, as well as on the method of addition.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (Proyect 2014-52928-C2

Assessing the rice flour-starch-protein mixtures to produce gluten free sugar-snap cookies

The mixture of rice flours, starches and proteins is common in gluten-free bakery products such as bread or cake. The aim of this study was to determine the effects of starch and/or protein addition in rice flour gluten-free cookie quality. For this purpose, the hydration and oil absorption properties of flour-starch-protein mixtures, dough rheology and quality cookie parameters (thickness, final diameter, spread factor, texture, colour and acceptability) were analysed. Generally, protein incorporation increased hydration properties of the mixture and dough consistency, producing cookies with limited spreading in the baking time, lower hardness values and darker colour. In particular, protein addition reduced the width up to 8.4% and the hardness up to 10.60 % (control versus 20% of protein inclusion). However, maize starch addition reduced hydration properties and gave rise to cookies with higher thickness and width, but the texture and colour were not affected by the starch. Cookies with higher protein content showed higher acceptability than cookies with higher starch content and no protein addition. Therefore, protein and starch can be used in order to adjust the desired cookie characteristics depending on the cookie formulation and the needs of manufacturers

Texture development in gluten-free breads: Effect of different enzymes and extruded flour

Producción CientíficaOne of the main problems with gluten-free breads is their texture and their rapid staling. In this work the influence of different enzymes (one protease, one lipase and two amylases) and of extruded rice flour on rice-bread texture and texture development was studied. For this purpose, the development of firmness, cohesiveness, resilience, springiness and chewiness was modelled and the parameters that define the initial values and the development of these characteristics were measured. The addition of lipase and extruded flour increased bread volume and reduced the initial firmness and hardening of breads. There was an early fall in cohesiveness and resilience, with minimum values reached a few days after elaboration. There were 99.9% significant correlations between bread density and firmness, springiness and chewiness development. PRACTICAL APPLICATIONS This methodology simplifies the study of gluten free breads textural parameters during storage and the result interpretation. Moreover, the correlation analysis has demonstrated that the number of textural parameters of gluten free breads to study can be reduced. Finally, the results obtained show that use of enzymes and extruded flours decreases bread staling